The Wisconsin Public Service Commission, in a Dec. 7 decision that was sent out on Dec. 10, approved an application from Wisconsin Power and Light, Wisconsin Public Service Corp. and Madison Gas and Electric for a $19.2m project to replace two cooling towers at the coal-fired Columbia power plant.
On Oct. 4, the commission received a joint application from the three plant co-owners for a Certificate of Authority to install new cooling towers at Columbia Energy Center (Columbia) Units 1 and 2, located in Columbia County, Wisc.
Columbia, which is operated by WP&L, consists of two coal-fired units with a total generating capacity of approximately 1,023 MW. Unit 1 (512 MW) was placed in service in 1975 and Unit 2 (511 MW) in 1978. This generating facility utilizes a 480-acre reservoir to cool the water needed to operate the plant. From April to October of each year when the ambient temperature is warm, the cooling towers are utilized because the existing lake is not large enough to cool the water necessary to operate the plant, the PSC noted. The replacement of the existing 30-year-old cooling towers with new units is the subject of this application.
Over the last several years the maintenance on the cooling towers has increased, primarily due to the deteriorating galvanized bolts and weakening of all the bolted wood-to-wood connections, the commission wrote. In July, eight wood beams supporting the water distribution piping failed in Tower B and it has been shut down since that time. If the two cooling towers are not replaced or do not undergo a total repair, they will likely suffer a significant structural failure, resulting in a complete collapse.
“The proposed reconstruction of the cooling towers is necessary for the long-term operation of Columbia,” the commission wrote. “Cooling tower designs have improved significantly over the last 30 years. The modern cooling towers would take advantage of stronger, corrosion and fire-resistant fiberglass-reinforced plastic materials with stainless steel bolting which are far less prone to rotting and deterioration than the original wood materials and galvanized bolting.”
Also, the utilities are installing SO2 scrubbers and baghouses at Columbia Units 1 and 2 to reduce SO2 and mercury emissions. Construction began in the first quarter of 2012 and is expected to be completed in 2014. These controls are expected to help meet requirements under the Clean Air Interstate Rule (CAIR) or some alternative to this rule that may be implemented, the Utility Maximum Achievable Control Technology (MACT) Rule and the Wisconsin State Mercury Rule.